Fiber preform of commingled fiber bundle for overmolding

ABSTRACT

A fiber preform for use in a resin transfer molding or liquid composite molding process and process of making the same are provided. The preform includes a substrate, a fiber bundle arranged on the substrate in a predetermined pattern and attached to the substrate by a plurality of stitches of a thread. The fiber preform is capable of being pre-formed into a three-dimensional shape. The fiber preform along with a sheet of preformed thermoset resin that impregnates at least a portion of the fiber preform forms a composite material. The fiber preform reinforces areas of stress concentration of a core to form a vehicle component.

RELATED APPLICATIONS

This application is a continuation in part of PCT Application SerialNumber PCT/IB2018/000856, filed Jul. 5, 2018, which in turn claimspriority benefit of U.S. Provisional Application Ser. No. 62/528,685filed on Jul. 5, 2017; 62/528,658 filed on Jul. 5, 2017; 62/540,771filed on Aug. 3, 2017; 62/540,830 filed on Aug. 3, 2017; 62/548,155filed on Aug. 21, 2017; 62/592,493 filed on Nov. 30, 2017; 62/592,481filed on Nov. 30, 2017.

FIELD OF THE INVENTION

The present invention in general relates to preforms for compositecomponents and in particular to sewn reinforced fiber preforms, and amethod of construction thereof based on thermoset resin overmolding ofthe preform.

BACKGROUND OF THE INVENTION

Weight savings in the automotive, transportation, and logistics basedindustries has been a major focus in order to make more fuel-efficientvehicles both for ground and air transport. In order to achieve theseweight savings, light weight composite materials have been introduced totake the place of metal structural and surface body components andpanels. Composite materials are materials made from two or moreconstituent materials with significantly different physical or chemicalproperties, that when combined, produce a material with characteristicsdifferent from the individual components. The individual componentsremain separate and distinct within the finished structure. A compositematerial may be preferred for many reasons: common examples includematerials which are stronger, lighter, or less expensive when comparedto traditional materials.

Composite materials are engineered or naturally occurring materials madefrom two or more constituent materials with significantly differentphysical or chemical properties which remain separate and distinct atthe macroscopic or microscopic scale within the finished structure.There are two categories of constituent materials: matrix andreinforcement. At least one portion of each type is required. The matrixmaterial surrounds and supports the reinforcement materials bymaintaining their relative positions. The reinforcements impart theirspecial mechanical and physical properties to enhance the matrixproperties. A synergism produces material properties unavailable fromthe individual constituent materials, while the wide variety of matrixand strengthening materials allows the designer of the product orstructure to choose an optimum combination.

The use of fiber and particulate inclusions to strengthen a matrix iswell known in the art. Well established mechanisms for the strengtheninginclude slowing and elongating the path of crack propagation through thematrix, as well as energy distribution associated with pulling a fiberfree from the surrounding matrix material. Liquid composite molding(LCM) and resin transfer molding (RTM) involve enveloping a preformstructure in a thermoset resin matrix. The curable thermoset resin isused both neat and loaded with reinforcing particulate and fiberfillers. The preform can add strength to the resulting vehiclecomponent, lower the overall density thereof through inclusion of a voidvolume, or a combination thereof.

There is a growing appreciation in the field of molding compositionsthat replacing in part, or all of the glass fiber in moldingcompositions with carbon fiber can provide improved componentproperties. However, the relative cost of carbon fiber relative to glasshas slowed the acceptance of such preforms in the automotive, heavytruck, farm equipment, and earth moving equipment mass markets. Yet, theuse of carbon fibers in composites, sheet molding compositions, andresin transfer molding (RTM) results in formed components with a lowerweight as compared to glass fiber reinforced materials. The weightsavings achieved with carbon fiber reinforcement stems from the factthat carbon has a lower density than glass and produces stronger andstiffer parts at a given thickness.

An additional hindrance to mass production of composite components andin particular vehicle components with LCM or RTM is the inefficiency ofpreform production and the scrap produced by providing cutouts ormodification of the preform prior to molding. Preform formation bycompressing chopped fibers relative to a preform mold is a comparativelyslow process and the resulting perform is difficult to handle.

Preforms are currently formed by laying up layers of woven fabric thatare cut to a desired shape. The cut sheets are then laid into a mold byhand and either the mold closed before thermoset curable resin injectioninto the mold (RTM) or after liquid composite molding (LCM). The currentprocess for forming a preform is slow and prone to error in placementeither through operator limitations or movement with resin flow as theresin is introduced or cured.

Thus, there exists a need for a more efficient method for forming anovel preform produced through the selective stitching of commingledfiber bundles to form a multilayer preform.

SUMMARY OF THE INVENTION

A fiber preform is provided for use in a resin transfer molding orliquid composite molding process that includes a substrate, a fiberbundle having one or more types of reinforcing fibers, and a thread. Thefiber bundle is arranged on the substrate and attached to the substrateby a plurality of stitches of the thread to form a first preform layerhaving a principal orientation.

A process of forming the fiber preform of for use in a resin transfermolding (RTM), liquid composite molding (LCM), thermoplasticovermolding, injection molding, or a like process includes providing asubstrate, applying a first layer of a fiber bundle to the substrate ina predetermined pattern having a principal orientation, stitching thefirst layer of the fiber bundle to the substrate using a thread,building up subsequent layers of the fiber bundle from the first layer,and stitching each of the subsequent layers to a preceding layer usingthe thread.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter that is regarded as the invention is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other objects, features, andadvantages of the invention are apparent from the following detaileddescription taken in conjunction with the accompanying drawings inwhich:

FIG. 1A is a schematic view of a reinforcement fiber bundle stitched toa substrate forming a fiber preform according to one embodiment of thepresent invention;

FIG. 1B is cross-sectional schematic view of the fiber bundle of FIG. 1;

FIGS. 2A-2D is a schematic illustrating a portion of inventive fiberpreform with a network of stitching material retained therein;

FIG. 3 is a magnified cross sectional view depicting the stitchingmaterial in a fiber preform;

FIG. 4 is a schematic view of a fiber bundle stitched to a substrateforming a fiber preform according to an embodiment of the presentinvention;

FIG. 5 is an exploded perspective view a multi-layered fiber preformaccording to an embodiment of the present invention;

FIG. 6 is a perspective view of the multi-layered fiber preform of FIG.5;

FIG. 7 is a perspective view of a selective commingled fiber bundlepositioning (SCFBP) assembly formed of layers of reinforcement fibersillustratively including glass fiber, carbon fiber, and polyaramidfibers that are retained with stitching in accordance with embodimentsof the invention using conventional interlayer orientation differences;

FIG. 8 is a schematic illustrating a SCFBP preform created from multiplecontinuous fiber bundles according to the present invention;

FIG. 9 is a cross section representation of a SCFBP preform, where Cstands for a carbon fiber rich commingled fiber bundle and G stands forglass fiber rich commingled fiber bundle, in accordance with embodimentsof the invention;

FIG. 10 is a schematic illustrating a SCFBP preform created according tothe present invention with a void underlying a top surface, with thenaming convention used in FIG. 9;

FIG. 11 is a cross section representation of a SCFBP form, where Cstands for a carbon fiber rich commingled fiber bundle and G stands forglass fiber rich commingled fiber bundle, in accordance with embodimentsof the invention;

FIG. 12 is a schematic illustrating a SCFBP preform created according tothe present invention inclusive of a disparate material strut;

FIG. 13A is a cross section representation of a SCFBP preform with areinforcing strut in accordance with embodiments of the invention, withthe naming convention used in FIG. 9;

FIG. 13B is a cross-section representation of a SCFBP preform with a topplaced reinforcing strut and an inverted preform as shown in FIG. 9 thatis complementary thereto;

FIGS. 14A-C are a schematic illustrating the steps of processing aninventive SCFBP preform into a component by via liquid compressionmolding; and

FIGS. 15A-C are a schematic illustrating the steps of processing aninventive SCFBP preform into a component by via resin transfer molding.

FIGS. 16A-16C are a sequence of schematic steps of processing aninventive SCFBP form into a vehicle component by melting anythermoplastic content of the SCFBP form;

FIG. 17 is a perspective view of a composite material according to anembodiment of the present disclosure;

FIG. 18 is a cross-sectional view of a composite material according toan embodiment of the present invention;

FIG. 19 is a cross-sectional view of a composite material according toanother embodiment of the present invention;

FIG. 20 is a perspective view of a composite material according toanother embodiment of the present disclosure;

FIGS. 21A-21D are cross-sectional schematic views of steps of a methodfor forming components formed of the composite material according to thepresent disclosure;

FIG. 22 is a perspective view of a multi-layered fiber preform accordingto an embodiment of the present disclosure;

FIG. 23 is a schematic view of a three-dimensional fiber preformaccording to an embodiment of the present invention on a preliminaryshaping mold;

FIG. 24 is a perspective view of a pre-shaping mold according toembodiments of the present disclosure;

FIG. 25 is a schematic view of a fiber preform having athree-dimensional shape;

FIG. 26 is a cross-sectional schematic view of the fiber preform of FIG.25;

FIGS. 27A-27F show exemplary cross sectional profile shapes of a fiberpreform according to embodiments of the present disclosure;

FIGS. 28A-28G are schematic drawings showing a process for forming afiber preform having a three-dimensional shape according to the presentinvention;

FIGS. 29A-29F show perspective views of various forms of shaping guidesaccording to embodiments of the present disclosure;

FIG. 30 is a perspective view of a composite material vehicle componentovermolded in a resin matrix according to an embodiment of the presentdisclosure;

FIG. 31 is perspective view of elements of the vehicle component of FIG.30 assembled together prior to being overmolded in a resin matrix;

FIG. 32 is a schematic top view of an insert reinforcing preformaccording to an embodiment of the present disclosure; and

FIG. 33 is a top view of an insert reinforcing preform according to anembodiment of the present disclosure.

DESCRIPTION OF THE INVENTION

The present invention has utility as a fiber preform of a light-weight,high-strength composite material and a process of creating the suchperforms by sewing a fiber bundle into desired preform shapes.Embodiments of the inventive preform may be formed using selectivecommingled fiber bundle positions (SCFBP). According to someembodiments, the fiber bundle includes only reinforcing fiber with nothermoplastic based fibers (e.g., nylon) in the selectively placedcommingled fiber bundle. In further embodiments, the fiber bundleincludes both reinforcing fibers and matrix fibers, such asthermoplastic based fibers. Embodiments of the inventive preform may bemulti-layered and need not have complete layers.

The reinforcing fibers used in embodiments of the preform are either100% carbon fiber, 100% glass fiber, 100% aramid, or a combination of atleast two of preceding reinforcing fibers. According to certainembodiments, the fiber bundle 14 includes matrix fibers in addition tothe reinforcing fibers. The matrix fibers being of a thermofusiblenature may be formed from a thermoplastic material such as, for example,polypropylenes, polyamides, polyesters, polyether ether ketones,polybenzobisoxazoles, polyphenylene sulfide; block copolymers containingat least of one of the aforementioned constituting at least 40 percentby weight of the copolymer; and blends thereof. The thermoplastic fibersare appreciated to be recycled, virgin, or a blend thereof. Thethermofusible thermoplastic matrix fibers have a first meltingtemperature at which point the solid thermoplastic material melts to aliquid state. The reinforcing fibers may also be of a material that isthermofusible provided their thermofusion occurs at a temperature whichis higher than the first melting temperature of the matrix fibers sothat, when both fibers are used to create a composite, at the firstmelting temperature at which thermofusibility of the matrix fibersoccurs, the state of the reinforcing fibers is unaffected.

According to some embodiments, the thread used to retain the fiberbundle is a thermoplastic thread, such as nylon. In other embodiments,the thread is a non-melt material such as a glass fiber thread, a carbonfiber thread, an aramid fiber thread, a metal wire, to provideadditional strength to the preform. As used herein, the term melting asused with respect to thermoplastic fibers or thread is intended toencompass both thermofusion of fibers such that a vestigial corestructure of separate fibers is retained, as well as a complete meltingof the fibers to obtain a homogenous thermoplastic matrix.

The substrate used to secure the fiber bundle attached with the threadmay be retained or removed prior to mold placement. Once formed, thepreform is then infiltrated with curable resin and cured as isconventional by either RTM, LCM, thermoplastic overmolding, injectionmolding, or the like. By setting an approximate three-dimensional (3D)shape of a fiber preform prior to insertion in a mold, the resultingvehicle component quality and throughput are enhanced while reducingproduct waste and human manipulation. The fusion of the stitching and/oradditional tac points throughout the fiber preform in the SCFBP preformis sufficient to retain the 3D shape of the preform needed for enhancedRTM, LCM, thermoplastic overmolding, or injection molding.

Embodiments of the inventive perform speed up the preform formationprocess and provide for more uniform parts. Furthermore, the ability tokeep all the fibers in the fiber bundle parallel (in a weave only halfare parallel in first direction and other half are perpendicular)positively affects the strength of a part formed with an embodiment ofthe preform. In addition, waste is reduced by eliminating the need tocut sheets to form the preform.

Embodiments of the inventive perform, formed with continuous fiberbundles are stronger than those produced from chopped fibers.Additionally, as SCFBP can use automated sewing machines, the speed andreproducibility are high compared to chopping fibers and formed preformstherefrom, while retaining the light weight of such preforms compared tometal preforms. Various composite components illustratively includingvehicle components are prepared with resort to selective commingledfiber bundle positioning (SCFBP) to selectively place co-mingled fibersthat are enriched in carbon fiber as a reinforcement relative to otherregion that rely on a relatively higher percentage of glass fiberreinforcement to create such a preform. In specific inventiveembodiments commingled fibers of glass, carbon, and aramid are used toform a yarn that has predictable strength, and where the ratio ofdifferent fiber types is varied to create different properties along agiven length. The commingled fiber based yarn may be used in theformation of the SCFBP preforms, and are able to be embroidered directlyinto complex shapes thereby eliminating trimming waste and inefficientusage of comparatively expensive carbon fiber. In specific inventiveembodiments, SCFBP preforms include from 3 to 20 layers that vary infiber types in three dimensions (3D). It is appreciated that number oflayers can be increased beyond 20 and is limited only by the ability tosew through preceding layers. Additionally, as SCFBP is based onsuccessive layer build up, new shapes of preforms can be developedrelative to chopped fiber preforms. As SCFBP is analogous tothree-dimensional printing, voids are readily formed by a successivelayer being stitched to a substrate with a void therebetween by notcompressing a fiber bundle to the substrate. Regardless of the shape thepreform, the preform is then overlayered with one or more of a woven ornonwoven fabric sheet. The fabric sheet being formed from thermoplasticfibers, glass fibers, polyaramid fibers, carbon fibers, or a combinationthereof.

According to some embodiments, the inventive multilayer preform isplaced on a mold platen and subjected to RTM, LCM, thermoplasticovermolding, or injection molding. In LCM, the liquid thermoset resinpoured over the preform and the thermoset cured in the shape of the moldplaten and at least one opposing mold platen, the platen collectivelybeing complementary to the shape of the desired composite component. InRTM, catalyzed, thermoset resin is pumped into a closed mold underpressure, displacing the air at the edges of the mold, until the preformis enveloped and the mold is filled with curing resin. Thermoset resinsoperative herein illustratively include vinyl esters, polyurethanes,epoxies, polyureas, benzoxazines, maleimides, cyanate esters, phenolicsand polyimides, each alone, a combination thereof, or in the presence ofa foaming agent. It is appreciated that the thermoset resin can be usedneat or loaded with chopped reinforcing fibers, particulate filler, orcombinations thereof. Reinforcing fiber operative in the thermoset resininclude those used in the continuous fiber bundles.

Composite components formed as vehicle component forms from an inventivethermoset resin overmolded preform illustratively include a vehiclebolster, vehicle post, a vehicle chassis, a pickup box, a cab loadfloor, a vehicle floor, a tailgate, a deck lid, a roof, a door panel, afender, a wheel well, and body panels; heavy truck components thatillustratively include the aforementioned and sleeping compartmentsections, farm equipment components that illustratively include drivecab body components; motor home floors and wall panels; and marineproducts such as decking, sound damping panels, and cockpit sections;and train car components illustratively including seats, flooring, roofsections, and walls.

It is to be understood that in instances where a range of values areprovided that the range is intended to encompass not only the end pointvalues of the range but also intermediate values of the range asexplicitly being included within the range and varying by the lastsignificant figure of the range. By way of example, a recited range offrom 1 to 4 is intended to include 1-2, 1-3, 2-4, 3-4, and 1-4.

SCFBP-technology offers several advantages including:

-   -   varying the angle of fiber placement during the lay-up process        freely between 0 and 360′;    -   repeated fiber placement on the same area allows for local        thickness variations in the fiber preform suited for a fiber        composite component,    -   the conversion of the desired fiber orientation in a fiber        placement pattern for an embroidery machine requires minor        development times and costs,    -   the process allows a near-net-shape production, which results in        low waste and optimal fiber exploitation,    -   the ability to process a variety of fibers such as natural,        glass, aramid, carbon (high strength and high modulus) and        ceramic fibers.

In order to efficiently change yarn compositions, multiple sewing headsmay be used, each sewing head loaded with a specific yarn compositionand adding those regions desired to have a given yarn composition.According to some embodiments, thermoplastic sewing thread is preferredto retain yarn in position as the shape of a component is developed,while in various embodiments a non-melt sewing thread is preferred. In aspecific inventive embodiment, the SCFBP form may be skinned with athermoplastic veil sheet prior to melting to yield the component.

Through the strategic placement of the fiber bundle, varying amounts ofdifferent reinforcing materials such as carbon fiber or matrix materialssuch as thermoplastic material are placed to yield a perform thatefficiently utilizes the comparatively expensive carbon fiber, forexample, content to toughen the resulting vehicle. According the presentinvention commingled fibers are retained in a series of two dimensionallayers that are sequentially constructed by SCFBP.

The reinforcement fibers in a commingled fiber bundle being glassfibers, polyaramid fibers, carbon fibers, or a combination of any of theaforementioned. In embodiments in which matrix fibers are present in thefiber bundle, the matrix fibers in the comingled fiber bundle may bethermofusible nature and may be formed from a thermoplastic materialsuch as, for example, polypropylenes, polyamides, polyesters, polyetherether ketones, polybenzobisoxazoles, polyphenylene sulfide; blockcopolymers containing at least of one of the aforementioned constitutingat least 40 percent by weight of the copolymer; and blends thereof. Thethermoplastic fibers are appreciated to be recycled, virgin, or a blendthereof. It is appreciated that the commingled fibers are eitherparallel to define a roving or include at some fibers that are helicallytwisted to define a yarn. It is appreciated that the physical propertiesof fibers retained in a helical configuration within a fixed matrix of acompleted composite component are different than those of a linearconfiguration, especially along the fiber axis.

An inventive preform is created by laying out one or more commingledfiber bundles on a substrate as a two-dimensional base layer thatdefines a shape of the preform with stitching applied to retain thecommingled fibers in a desired placement on the substrate. As isconventional to SCFBP, the substrate can be removed after production ofthe form, else it is retained and thereby incorporated into theresulting composite component. In various inventive embodiments, thestitching is a thermoplastic thread, non-melt material thread, or ametal wire. The thermoplastic thread in some inventive embodiments isformed of materials operative herein that illustratively include nylon,polypropylenes, polyamides, polyesters, polyether ether ketones,polybenzobisoxazoles, block copolymers. It is appreciated that thethread diameter and melting temperature of the thread used for stitchingare variables that are readily selected relative to the properties ofcommingled fiber bundle. In some embodiments, the substrate is retainedand adds the toughness of the resulting vehicle component. Exemplarysubstrates for SCFBP are disposable films, thermoplastic fabrics,fiberglass fabric, carbon fiber fabrics, polyaramid fabrics, andco-blends of any of the aforementioned, alone or in combination withthermoplastic or naturally occurring fibers. Thermoplastic fibers orfabrics include the aforementioned polymers recited above, whilenaturally occurring fibers illustratively include cotton, linen, jute,bamboo and silk.

As used herein, any reference to weight percent or by extensionmolecular weight of a polymer is based on weight average molecularweight.

Referring now to FIG. 1A, a fiber preform 10 according to one embodimentof the present invention is shown. The fiber preform 10 includes asubstrate 12 which acts as a foundation or base upon which a fiberbundle 14 is applied. The fiber bundle 14 includes one or morereinforcing fibers of carbon fiber, glass fiber, and aramid. In aspecific inventive embodiment, the fiber bundle 14 is made of comingledreinforcing fibers, illustratively including those made of carbon,glass, and aramid fibers. As noted each of the bundles 14 may be madeexclusively of reinforcing material. According to embodiments, the fiberbundle 14 further includes a matrix material, such as a thermoplasticmaterial such as, for example, polypropylenes, polyamides, polyesters,polyether ether ketones, polybenzobisoxazoles, polyphenylene sulfide;block copolymers containing at least of one of the aforementionedconstituting at least 40 percent by weight of the copolymer; and blendsthereof. The thermoplastic fibers are appreciated to be recycled,virgin, or a blend thereof. According to various embodiments, the fiberbundle 14 also includes electrical wiring. In such embodiments, theelectrical wiring and wiring harness is internalized in within the fiberpreform, thereby simplifying the resulting vehicle component andreducing vibrationally induced wear observed in traditional electricalharnesses. Electrically conductive insulated wire is also stitched bythe SCFBP process into the form to create pre-selected electricalpathways. The final panel is them formed by melting any thermoplasticfibers within the SCFBP form in contact with at least one mold platencomplementary to the finished vehicle component to form a vehicle panelsuch as a dashboard, body panel, door component, roof components, ordecklids

The substrate 12 may be a tear-off fabric or paper or other suitablematerial. The fiber bundle 14 is applied to the substrate 12 by aselective comingled fiber bundle positioning (SCFBP) method and attachedto the substrate 12 by a plurality of stitches 18 a-18 d of a thread.The plurality of stitches 18 a-18 d are shown in various zig-zag stitcharrangements. For example, the stitches may be closely spaced stitches18 a and 18 d or spaced apart by a greater linear distance such asstitches 18 b and 18 c. The stitches may be continuously connected alongthe fiber bundle 14 such as stitches 18 a, or the stitches may bediscrete and separate single stitches 18 c or separate groups ofstitches such as stitches 18 b and 18 d. In the case of thermofusiblethread, the plurality of stitches 18 may also attach the fiber bundle toitself. The fiber bundle 14 may be applied in any arrangement on thesubstrate 12.

The arrangement of the fiber bundle 14 on the substrate 12 may generallyresemble the shape of the designed final composite material component,for example a structural component of an automobile. Alternatively, thearrangement of the fiber bundle 14 on the substrate 12 may be designedto have a shape that corresponds to an edge or a portion of the finalcomposite material that is to be reinforced with the preform. The fiberbundle 14 may be arranged in a principal direction, in other words in aprincipal direction of stress of the final composite material component.In FIG. 1A, the principal orientation of the fiber bundle 14 is along alongitudinal axis X of the fiber preform 10, however, other suitableorientations are also possible and may be used based on the designconsiderations and stresses for each composite material part. FIG. 1Aillustrates only a first preform layer 11.

It is appreciated that the comingled fibers are either parallel todefine a roving or include at some fibers that are helically twisted todefine a yarn. It is appreciated that the physical properties of fibersretained in a helical configuration within a fixed matrix of a completedcomponent are different than those of a linear configuration, especiallyalong the reinforcing fiber axis. The relative number of reinforcingfibers is highly variable in the present invention in view of thedisparate diameters of glass fibers, polyaramid fibers, and carbonfibers.

As shown in FIG. 1B, the fiber bundle 14 may include a subset ofcomingled fiber bundle fibers 15, a subset of roving fibers 16, or acombination thereof. The comingled fiber bundle fibers 15 are helical orspun while the roving fibers are parallel to one another and nothelical. The fiber bundle 14 may be a single continuous fiber bundle fedfrom a spool in the SCFBP process to form the fiber preform 10.Alternatively, the fiber preform 10 may be formed of multiple separatefiber bundles. Using multiple fiber bundles to form the fiber preformallows for fiber bundles having different reinforcing fibers, whichenables tuning of the fiber preform insert. Additionally, increasing thenumber of fiber bundles used in the SCFBP process speeds the fiberpreform manufacturing process, which increases throughput andefficiency. The multiple fiber bundles may be applied to the substratetogether starting from the same end of the substrate or they may beapplied spaced apart with each beginning at opposite ends of thesubstrate and converging at a middle region between the ends of thesubstrate. The thread that attaches the fiber bundle 14 to the substrate12 may be a thermoplastic thread such as nylon or polyethylene material.Alternatively, the stitching thread may be a non-melt material such asor a glass fiber thread, a carbon fiber thread, an aramid fiber thread,or a metal wire.

The fiber preform 10 is tunable and easily changed and adapted forvarying design requirements. The properties and characteristics of thefiber preform may be changed and modified based on controllingparameters of the various components of the fiber preform includingparameters of the fiber bundle 14, the thread material, and theplurality of stitches 18 a-18 d. Parameters of the fiber bundle mayinclude, but are not limited to, a diameter of the fiber bundle.Parameters of the thread may include, but are not limited to, a denierof the thread, a composition of the thread, and a melting temperature ofa thermoplastic thread when used. The parameters of the plurality ofstitches 18 a-18 d may include, but are not limited to, a lineardistance between the stitches and a tension of the stitches. The detailsof forming such a preform are detailed in a co-pending provisionalapplication entitled “VEHICLE COMPONENT BASED ON SELECTIVE COMINGLEDFIBER BUNDLE POSITIONING FORM” Ser. No. 62/486,288 filed Apr. 17, 2017.

Thread and Stitches

Referring again to FIG. 1A, the plurality of stitches 18 are shown invarious zig-zag stitch arrangements. For example, the stitches may beclosely spaced stitches 18 a and 18 d or spaced apart by a greaterlinear distance such as stitches 18 b and 18 c. The stitches may becontinuously connected along the fiber bundle 14 such as stitches 18 a,or the stitches may be discrete and separate single stitches 18 c orseparate groups of stitches such as stitches 18 b and 18 d. Theplurality of stitches of thread may also attach the fiber bundle toitself. Increasing the number of stitches used to attach the fiberbundle to the substrate increases the thread to fiber bundle ratio,which is yet another tunable parameter of the fiber preform. The tensionof the plurality of stitches may also be controlled. For example, lowtension stitches results in a lose attachment of the fiber bundle to thesubstrate. In embodiments in which the thread is a thermoplastic thread,low tension stitches result in more thermoplastic thread material in thefiber preform. Alternatively, high tension stitches result in a tightattachment between the fiber bundle and the substrate, an ability to putthe fiber bundle in compression, and less thermoplastic thread materialin the fiber preform when the thread is a thermoplastic thread material.The thread to fiber bundle ratio may be controlled according to designconfigurations by balancing the number, arrangement of, linear distancebetween, and tension of the plurality of stitches.

In embodiments in which the thread is a thermoplastic thread, thethermoplastic thread intersects itself at various points throughout thefiber preform 10. When the fiber preform 10 is heated to the meltingtemperature of the thermoplastic thread, the thermoplastic thread fusesto itself at those intersections to form tacking points. Increasing thenumber of stitches used to attach the fiber bundle to the substrateincreases the number of tacking points.

According to some embodiments the thread for attaching the fiber bundle14 to the substrate 12 is a thermoplastic thread. The thermoplasticthread may be a nylon or polyethylene material. The identity of thethermoplastic thread may be selected to have a melting temperature thatis lower than the melting temperature of any optional thermoplasticfibers of the fiber bundle 14. At this lower second melting temperature,the solid thermoplastic thread melts to a liquid state. At this lowermelting temperature, thermofusibility of only the thermoplastic threadoccurs, while the state of any thermoplastic fibers of the fiber bundleis unaffected. According to various embodiments of the presentinvention, the melting temperature differential between the meltingtemperature of the thermoplastic fiber of the fiber bundle (firstmelting temperature) and the melting temperature of the thermoplasticthread (second melting temperature) may be at least 50° C., while inother embodiments the melting temperature differential may be more than100° C.

As shown in FIGS. 2A-2D and 3, a partially transparent sectional view ofa preform is shown generally at 10. The various layers sequential layersare shown is being laterally displaced, but it should be appreciatedthat these layers can be sewn overlaid. A commingled fiber bundle 14(surrounded by the stitches and shown in ghost) is retained to asubstrate 12 with stitching material generally at 18. The substrate 12which acts as a foundation or base upon with the commingled fiber bundle14 is applied. The substrate 12 may be a tear-off fabric or paper orother suitable material. It is appreciated that a conventional sewingmachine head forms a chain stitch using a top stitching material thread18 e while a bobbin below the substrate 12 provides a lower stitchingmaterial thread 18 f. In certain inventive embodiments, the commingledfiber bundle 14 is laid out in a base layer 11 in generally parallellines with a given orientation on the substrate 12 as shown in FIGS.2A-2D. The stitching material 18 extends along the length of thecommingled fiber bundle 14 and generally orthogonal to the substrate 12to form base layer stitches 24 having a vertical extent, R. In thiscontext, “generally orthogonal” means angles in which the top thread 16a is 90±20 degrees relative to a substrate 14 at the point of themeasured stitch.

The base layer 11 has a given orientation, while a second layer 20 a,and a first successive layer 20 b have like orientations of commingledfiber bundles 14 and the corresponding stitching 18, or in certainembodiments, the embodiments the layers 20 a and 20 b are applied with acommingled fiber bundle displayed at different orientations relative tothe plane of the base layer 11. For example, layers 20 a and 20 b aredeployed at angles of 90 degrees and 0 degrees, respectively. The secondlayer 20 a is overlaid onto the base layer 11 and the stitching material18 applied in the same way to tack the commingled fiber bundle 14thereof to the substrate 12 with stitches 26 having a vertical extent ofapproximately 2R. Similarly, the first successive layer 20 b applied onsecond layer 20 a has stitches 28 having a vertical extent ofapproximately 3R.

The stitching material 18 is applied with a preselected tension,stitching diameter, stitch spacing. The stitching 18 is typicallypresent in an amount of from 0.1 to 7 weight percent of the commingledfiber bundle 14.

It has been found that the stitching forming a network of loopsextending through the thickness of a fiber preform are able to dissipateforces on the component and thereby make the preform have moreattractive toughness relative to a component lacking unfused stitchingand as a result, an inventive fiber preform is lighter and lessexpensive to produce.

By increasing the distance between stitches and using fewer stitches toattach the fiber bundle to itself and to the substrate, manufacturingthroughput of fiber preform inserts for over molding is increased.Additionally, adding secondary tack points throughout the fiber preformallows for maintaining or increasing the shape-retaining rigidity of thefiber preform insert in addition to the enhanced throughput.

According to various embodiments, the plurality of stitches 18 includesonly as many stitches 10 as is necessary to secure the fiber bundle 14to the substrate 12. For example, the number of stitches necessary tosecure the fiber bundle 14 to the substrate 12 will depend in part onthe arrangement of the fiber bundle 14 on the substrate 12 and the sizeof the fiber preform 10. Generally, the number of stitches 18 necessaryto secure the fiber bundle 14 to the substrate means the stitches 18 arecapable of holding the fiber bundle generally or approximately in itsarranged position relative to the substrate 12. For example, thestitches may be discrete stitches 18 a, 18 b, 18 c positioned long thelength of the fiber bundle 14, or the stitches may be continuousstitches 18 d. Generally, the goal of the stitches 18 is to secure thefiber bundle to the substrate with as few stitches as possible, therebyspeeding the manufacturing time and increasing throughput of the fiberpreform 10. As shown in FIG. 4, for example, the stitches 18 a may belocated at the ends of the fiber bundle 14. Alternatively, or incombination, the stitches 18 b may be located at positioned where thefiber bundle 14 changes direction in its arrangement on the substrate12; for example, at the curves or bends in the fiber bundle.Alternatively, or in combination, the stitches 18 c may be located inlinear portions of the fiber bundle. The plurality of stitches of threadmay also attach the fiber bundle to itself. The tension of the pluralityof stitches may also be controlled. For example, low tension stitchesresult in a lose attachment of the fiber bundle to the substrate andmore thread material in the fiber preform. Alternatively, high tensionstitches result in a tight attachment between the fiber bundle and thesubstrate, an ability to put the fiber bundle in compression, and lessthread material in the fiber preform.

As shown in FIG. 4, the plurality of secondary tack points 17 throughoutthe fiber bundle 14 further attach the fiber bundle 14 to the substrate12, attach the fiber bundle 14 to itself, or a combination thereof.According to various embodiments, the plurality of secondary tack points17 are configurations of hot glue, sprayed on adhesive, fused pointsformed by ultrasonic welding, fused points formed by melting of thethermoplastic thread in embodiments that utilize a thermoplasticstitching thread. In embodiments in which the secondary tack points 17are formed by melting the thermoplastic thread, the thermoplastic threadis melted by heating the fiber preform 10 to the melting temperature ofthe thermoplastic thread to fuse stitches of the thermoplastic thread toother stitches of the thermoplastic thread. Alternatively, thethermoplastic thread may be melted and fused by spot ironing or flatironing the fiber preform 10. According to yet another form of thepresent disclosure, a thermoplastic powder is applied to the fiberbundle before or after the fiber bundle 14 is arranged on the substrate12. The thermoplastic powder melts when heated and cures to form theplurality of secondary tack points. The plurality of secondary tackpoints 17 assist with speeding up the manufacturing process for such afiber preform 10 by providing strength and stability to the preform 10while allowing the number of stitches 18 to be reduced.

As shown in FIG. 5, the fiber preform 10 according to one embodiment ofthe present invention includes the first preform layer 11 and at leastone subsequent preform layer 20 formed of the fiber bundle 14 arrangedupon the first preform layer 11. The plurality of secondary tack points17 are in part positioned between the first preform layer 11 and the atleast one subsequent preform layer 20. According to further embodiments,each subsequent preform layer 20 is arranged on a preceding preformlayer and attached to the preceding preform layer by additional stitchesof the thread, by additional secondary tack points, or a combinationthereof. While the example fiber preform 10 shown in FIG. 5 includesfour subsequent preform layers for a total of five preform layersincluding the first preform layer, it is appreciated that the at leastone subsequent preform layers may include two to twenty layers. Thefiber bundle 14 that forms each of the subsequent preform layers may bea continuation of the fiber bundle of the preceding preform layer or itcould be a separate piece of fiber bundle.

In FIG. 5, the plurality of stitches of thread are not shown for thesake of clarity, but it will be readily understood that each layer offiber bundle 14 is attached to the preceding layer and/or to itself by aplurality of stitches identical to those explained throughout thepresent disclosure. Additionally, each layer of fiber bundle 14 may alsobe attached to the preceding layer and/or itself by secondary tackpoints.

To achieve a quickened manufacturing process, according to variousembodiments, stitching the first layer 11 of the fiber bundle 14 to thesubstrate 12 includes stitching using a plurality of stitching heads.Similarly, in certain embodiments, the stitching includes stitching onlyas many stitches as is necessary to secure the fiber bundle 14 to thesubstrate 12. As discussed above, the number of stitches necessary tosecure the fiber bundle to the substrate may vary based on thepredetermined pattern and generally means the fewest number of stitchessuch that the fiber bundle remains in the predetermined pattern relativeto the substrate. In some embodiments, this includes stitching the firstlayer 11 of the fiber bundle 14 to the substrate 12 at a first end and asecond end using stitches 18 a. Alternatively or additionally, thestitching includes stitching the fiber bundle to the substrate at aplurality of curves in the predetermined pattern using stitches 18 b.

According to various embodiments, creating secondary tack points 17throughout the first layer 11 of the fiber bundle 14 to attach the fiberbundle 14 to itself, to the substrate 12, or a combination thereofincludes applying hot glue to the fiber bundle as it is arranged on thesubstrate. The hot glue may be applied in dots, lines, or other suitableconfigurations. The secondary tack points 17 may be applied between thesubstrate and the fiber bundle, between portions of the fiber bundle, ora combination thereof. Some embodiments provide creating the secondarytack points 17 by applying a spray on adhesive to the first preformlayer 11. Such an adhesive could be applied to the substrate 12 beforethe fiber bundle 14 is arranged upon it. Alternatively, or additionally,the adhesive spray may be applied to the fiber bundle 14 as the fiberbundle 14 is arranged on the substrate or after the fiber bundle isarranged on the substrate.

In some embodiments, creating the secondary tack points 17 includesultrasonically welding points throughout the fiber bundle to fuse thefiber bundle to itself. The fiber bundle may fuse to itself whenthermoplastic fibers in the fiber bundle or thermoplastic thread fromthe plurality of stitches melts upon being heated and fuses togetherupon cooling. In other embodiments, heating of the fiber preform 10 isused to create the secondary tack points 17. Heating the fiber preformto a temperature to melt the thermoplastic thread used for stitching thefiber bundle to the substrate melts the thread of those stitches tocreate the tack points while leaving the rest of the fiber preformunchanged. Alternatively, or additionally, heating the fiber preform tothe temperature that melts any thermoplastic fibers in the fiber bundlealso creates tack points while leaving the rest of the fiber preform,with a higher melting temperature, unchanged. In some embodiments, thesecondary tack points 17 are created by applying a thermoplastic powderto the fiber bundle 14. The powder may be applied to the fiber bundlebefore or after the fiber bundle is arranged on the substrate. Once thepowder is applied to the fiber bundle, the fiber preform 10 is heated tomelts the thermoplastic powder. The secondary tack points 17 are formedwhen the melted thermoplastic powder cures or hardens when cooled.

According to various embodiments of the present disclosure, the methodfurther comprises applying a second layer 20 of the fiber bundle 14 onto the first layer 11 of the fiber bundle in a second predeterminedpattern and applying secondary tack points 7 between the first fiberbundle layer 11 and the second fiber bundle layer 20. Such secondarytack points 17 are created by any of the methods described above forcreating secondary tack points. These secondary tack points 17,therefore, assist with holding the layers of the fiber bundle together.The second fiber bundle layer and any additional subsequent layers arebuilt-up from the first layer and similarly stitched to a precedinglayer using thread or thermoplastic thread. The second predeterminedpattern may be the same as the first predetermined pattern. The secondpredetermined pattern may be angularly offset from the orientation ofthe first preform layer.

Arrangement of Fiber Bundle on Substrate

As further shown in FIG. 5, the fiber preform 10 according to oneembodiment of the present invention includes the first preform layer 11with its principal orientation along the X axis and a plurality ofsubsequent preform layers 20 a, 20 b, 20 c, 20 d formed of the fiberbundle 14 successively stacked from the first preform layer 11. Eachsubsequent preform layer 20 a, 20 b, 20 c, 20 d is arranged on apreceding preform layer and attached to the preceding preform layer byadditional stitches of the thread. For example, the first subsequentpreform layer 20 a is arranged on and attached to the preceding firstpreform layer 11, the second subsequent preform layer 20 b is arrangedon and attached to the preceding first subsequent preform layer 20 a,the third subsequent preform layer 20 c is arranged on and attached tothe preceding second subsequent preform layer 20 b, and the fourthsubsequent preform layer 20 d is arranged on and attached to the thirdsubsequent preform layer 20 c. While the example fiber preform 10 shownin FIG. 5 includes four subsequent preform layers for a total of fivepreform layers including the first preform layer, it is appreciated thatthe plurality of subsequent preform layers may include two to twentylayers. The fiber bundle 14 that forms each of the subsequent preformlayers may be a continuation of the fiber bundle of the precedingpreform layer or it could be a separate piece of fiber bundle.

In FIG. 5, the plurality of stitches of thread are not shown for thesake of clarity, but it will be readily understood that each layer offiber bundle 14 is attached to the preceding layer and/or to itself by aplurality of stitches identical to those explained throughout thepresent disclosure. It is appreciated that the stitches used to secureeach subsequent preform layer could extend to the substrate, for exampleif it is desired to have a higher concentration of thread present in thefiber preform. Alternatively, the stitches used to attach eachsubsequent preform layer can extend to the preceding preform layer,which allows for a more efficient preform manufacturing process in thatthe penetration depth of the stitching needle need not be alteredbetween the various layers of fiber bundle. After at least one of thesubsequent preform layers has been stacked and attached to the firstpreform layer, the substrate may be removed from the fiber preform.Alternatively, the substrate may remain attached to the first preformlayer until all of the subsequent preform layers have been stacked onand attached to the preceding preform layer, or the substrate can remainattached to the fiber preform throughout the composite materialmanufacturing process.

As shown in FIG. 5, the orientation of each subsequent preform layer maybe offset from the orientation of the preceding preform layer.Offsetting the orientation of the various layers enables strength inmultiple directions. The orientation of each subsequent preform layermay be offset from that of the preceding preform layer by an angulardisplacement a relative to the principal orientation of the first layer,for example the X axis. The layers can be overlaid with a variety ofangular displacements relative to a first layer. If zero degrees isdefined as the long axis X of the first preform layer 11, the subsequentpreform layers are overlaid at angles of 0-90°. For example, in thefiber preform 10 shown in FIG. 5, the angular displacement a is 45°resulting in a 0-45-90-45-0 pattern of preform layers. Further specificpatterns illustratively include 0-45-90-45-0, 0-45-60-60-45-0,0-0-45-60-45-0-0, 0-15-30-45-60-45-30-15-0, and0-90-45-45-60-60-45-45-90-0. While these exemplary patterns are for from5 to 10 layers of uni-directional fibers, it is appreciated that thefiber preform may include from 3 to 20 layers. It is appreciated thatthe preform layers may be symmetrical about a central layer, in the caseof an odd number of layers, or about a central latitudinal planeparallel to the layers. That is, as shown in FIG. 5, the orientation ofthe first layer 11 and the last of the subsequent preform layers 20 dare generally the same while the first subsequent layer 20 a and thirdsubsequent preform layer 20 c are symmetrical with one another, suchthat the layers 11, 20 a, 20 c, and 20 d are symmetrical about thecenter layer 20 b. Providing the various preform layers with symmetricalorientations enables the fiber preform 10 to resist warping. In additionto the substantially linear pattern of comingled fiber bundlepositioning depicted in drawings with interspersed swithchbacks, it isappreciated that other patterns operative herein illustratively includespirals, and any space filling curve such as a Peano curve, dragoncurve, or Sierpinksi curve.

As shown in FIG. 6, the fiber preform 10 having of a plurality ofpreform layers has a generally two-dimensional shape, that is, while thevarious layers give the fiber preform 10 a thickness, the fiber preformis substantially flat or planar.

FIG. 7 is a perspective view of a selective commingled fiber bundlepositioning (SCFBP) assembly 40 formed of layers of reinforcement fibers42 illustratively including glass fiber, carbon fiber, and polyaramidfibers that are retained with stitching 18. The angles of the individuallayers (L1, L2, L3, L4, L5) of reinforcement fibers 42 are varied duringthe lay-up process. Each of the individual layers (L1, L2, L3, L4, L5)may be composed of a single type of reinforcement fiber where the fibersare arranged parallel to each other in an individual layer.

Process

According to embodiments, an inventive fiber preform 10 is formed byproviding a substrate 12, applying a first layer 11 of fiber bundle 14of one or more of glass, carbon, and polyaramid fibers and securing thefibers to the substrate 12 in a predetermined pattern having a principalorientation, for example along the X axis. The process continues bystitching the first layer 11 of the fiber bundle 14 to the substrate 12using a thread. In some embodiments the thread is a thermoplastic threadhaving a melting temperature that is lower than the first meltingtemperature. Subsequent layers 20 a, 20 b, 20 c, 20 d of the fiberbundle 14 are then built-up from the first layer 11 and similarlystitched to a preceding layer using the thread. As described above, thefiber preform 10 produced according to the process of the presentdisclosure may have subsequent preform layers that are offset from thepreceding layer by an angular displacement relative to the principalorientation of the first layer 11. The angular displacement may beanywhere from 0-90 degrees or, for example, may be any one of 15degrees, 30 degrees, 45 degrees, 60 degrees, 75 degrees, and 90 degrees,or a combination of various angles. The process may also includeremoving the substrate 12 once the preform layers have been built-upform the first layer 11.

FIG. 8 shows an inventive preform 110 is in the process of beingcreated. A spool 60 contributes a reinforcing fiber 62, while at leastone additional spool 60′ and 60″ of reinforcing fiber or matrix fiber iscombined with the reinforcing fiber 60 to yield a commingled fiberbundle 112. According to embodiments, the modification of the percentageof carbon fiber reinforcing fiber relative to other types of reinforcingfiber used in preform 110, the total percentage of reinforcing fiber, ora combination thereof are readily controlled. While spool 60 contributescarbon fiber 62 to the commingled fiber bundle 112, spool 60′ isprovides glass fiber 62′ or polyaramid, shown generically at 62″. It isappreciated that multiple additional spools of various types ofreinforcement fibers or matrix fibers beyond the three depicted in FIG.8 are readily used to form a commingled fiber bundle 112, yet theseadditional spools are not depicted for visual clarity. The process ofcreating a commingled fiber bundle 112 is routinely performedcommercially. It is appreciated that any given reinforcing fiber ormatrix fiber 62, 62′, or 62″ is readily cut, creating a length ofcommingled fiber bundle 112. Upon feeding the cut end of the depletedfiber back into the cording or other conventional equipment that affordsthe commingled fiber bundle 112 as an output, and is inserted in aportion of the preform 110.

The commingled fiber bundle 112 is conveyed to a substrate 114 by aguide pipe 116 to lay out the commingled fiber bundle 112 inpredetermined pattern on the substrate 114. A conventional sewingmachine head operating a needle 118 with a top thread 120 tacks thecommingled fiber bundle 112 with stitches 122, for example ofthermoplastic thread. A bobbin below the substrate 114, includes abobbin with a lower thread are not shown, and are conventional to sewingmachines. The top thread 120 and the bottom thread are thermoplasticthreads, glass fiber threads, carbon fiber threads, aramid fiberthreads, or metal wires, according to embodiments. In certain inventiveembodiments, the commingled fiber bundle 112 is laid out in a base layer124 in generally parallels lines with a given orientation. Switchbackturn regions 126 are commonly used to lay out parallel lines ofcommingled fiber bundle 112. As shown in FIG. 8, base layer 124 has anorientation of 30 degrees, while a first successive layer 128, and asecond successive layer 130 have orientations of 90 degrees and 0degrees, respectively. This is best seen in the notch region 132 in thepreform 110. The commingled fiber bundle 112 that is enriched in carbonfiber is depicted as shaded and designated at 112′ relative tocomparatively carbon fiber depleted commingled fiber bundle 112″. As aresult of the present invention, the preform 110 includes specificfeatures such as the notch region 132 that conventionally would be cutfrom a base piece. In this way, the present invention eliminates thecutting step, as well as the associated waste generation. In addition tothe substantially linear pattern of commingled fiber bundle positioningdepicted in FIG. 8 with interspersed swithchbacks, it is appreciatedthat other patterns operative herein illustratively include spirals, andany space filling curve such as a Peano curve, dragon curve, orSierpinksi curve.

If zero degrees is defined as the long axis of the base layer 124, thesubsequent layers are overlaid at angles of 0-90°. For example, anangular displacement between adjacent layers is 45° resulting in a0-45-90-45-0 pattern of layers. Further specific patterns illustrativelyinclude 0-45-90-45-0, 0-45-60-60-45-0, 0-0-45-60-45-0-0,0-15-30-45-60-45-30-15-0, and 0-90-45-45-60-60-45-45-90-0. While theseexemplary patterns are for from 5 to 10 layers of directional SCFBP, itis appreciated that the preform 110 may include from 3 to 20 layers. Itis appreciated that the form layers may be symmetrical about a centrallayer, in the case of an odd number of layers, or about a centrallatitudinal plane parallel to the players.

The stitching 122 is applied with a preselected tension, stitchingdiameter, stitch spacing. The stitching 122 is typically present in anamount of from 0.1 to 7 weight percent of the commingled fiber bundle112′ or 112″.

While FIG. 8 only shows three layers, it is appreciated that a preform110 is readily formed with up to 20 layers with the only technical limitbeing the length of the travel of the needle 118. While commingled fiberbundle 112″ has a first ratio of reinforcement fibers to the otherreinforcement fibers, commingled fiber bundle 112′ have a differentratio therebetween. These ratios in a prototypical embodiment of thepresent invention varying between layers 124 and 128 of the preform 110.

A cross-sectional view of an exemplary form similar to form 110 is shownin FIG. 9 with seven layers, where C denotes a carbon fiber enrichedcommingled fiber bundle 112′ and G denotes a carbon fiber depletedcommingled fiber bundle 112″ to illustrate regions of selectivetoughening to enforce the edges and center of the form. In this waycarbon fiber is used efficiently. In contrast to the form 110, withadjacent layers varying in angle, FIG. 9 shows the adjacent layersparallel for visual clarity. No stitches are shown for visual clarity.

Referring again to FIG. 8, embodiments may include a second conventionalsewing machine head′ operating a needle 118′ with a top thread 220 tacksa devoted carbon depleted commingled fiber bundle 112″ with stitches122′. Duplicate spools 60, 60′, and 60″ feed reinforcement fibers 62,62′, and 62″ respectively to a duplicate guide pipe 116′ to formcommingled fiber bundle 112″. A second bobbin below the substrate 114,includes a bobbin with a lower thread are not shown, and areconventional to sewing machines. The top threads 120 and 220, can be thesame or different and likewise the bottom threads. The needle 118 inFIG. 8 now is devoted to only applying a uniform commingled fiber bundle112′ that is enriched in carbon fiber relative to 112″. While only twoseparate sewing heads are shown in FIG. 8, it should be appreciated thatadditional sewing heads are readily used to simultaneous stitchcommingled fiber bundles to create a form. This being especially thecase when the form is for a large area form as might be employed in avehicle component such as a floor. Patterns as detailed with respect toFIG. 8 are readily formed in this embodiment.

FIG. 10 is a cross-sectional view of a SCFBP preform created accordingto the present invention per FIG. 8 with two partial layers 212extending from a top surface of a seven-layer inventive preform, withthe common naming convention used with respect to FIG. 9. A partiallayer 212 is formed simply by applying a commingled fiber bundle as anincomplete top layer during the SCFBP process. In certain inventiveembodiments, the partial layer 212 is a majority by weight in partiallayer 212 is the carbon enriched commingled fiber bundle 112′, in whichlike reference numerals have the meaning previously ascribed thereto. Instill other inventive embodiments, the partial layer 212 is solely thecarbon enriched commingled fiber bundle 112′. In contrast to the preform110 or 210, with adjacent layers varying in angle, FIG. 10 shows theadjacent layers parallel for visual clarity. No stitches are shown forvisual clarity.

A cross-sectional view of an exemplary form similar to form 210 is shownin FIG. 11 with seven layers, where C denotes a carbon fiber enrichedcommingled fiber bundle 112, G denotes a carbon fiber depletedcommingled fiber bundle 112 to illustrate regions of selectivetoughening to enforce the edges and center of the form, and W denoteswiring 121. In this way carbon fiber is used efficiently to toughenwhile the part includes electrical wiring. FIG. 11 shows the adjacentlayers parallel for visual clarity. No stitches are shown for visualclarity.

As shown in FIG. 12, in which like reference numerals have the meaningpreviously ascribed thereto, an inventive preform 310 is in the processof being created. This embodiment varies from that detailed with respectto FIG. 8 in that a mechanically supporting strut 312 is stitched intothe preform 310. The strut 312 is in certain inventive embodiments afully density composite material having a higher stiffness per unit arearelative to a vehicle component area created by melting thethermoplastic content of preform 110 or curing resin to impregnate thepreform 110, a sewable polymeric foam that is either open-celled orclose-celled, or an expanded structure. According to some embodiments,the strut 312 is a printed circuit board configured to work withelectrical wiring that is included in the fiber bundle according tovarious embodiments. It is appreciated that a fully densified strut 312is formed of carbon fiber rich composite or sewing needle pierceablemetal, the aforementioned with either smooth surfaces or contoured toimprove strength properties through corrugation, dimpling, or imposing ahexagonal pattern embossment therein. Preformed holes 314 in the insert312 are present in certain inventive embodiments that are sized andspaced to receive thread 120. In an alternate embodiment, the strut 312is an expanded hexagonal or rhombohedral holes 316 formed of metal orplastics. Aluminum honeycomb grid core mesh is exemplary thereof. Instill other inventive embodiments, the strut 312 is placed in a toplayer of a preform 310 to avoid having to maintain alignment with holes314 or otherwise continue to stitch and a second form, such as 110 isinverted and laid on top of the strut 312 to encompass the strut 312 inSCFBP forms. In still other inventive embodiments, a veil is overlaid onthe top surface of form 310 to encompass a top layer strut inthermoplastic material. It is appreciated that an insert 312 with athread hole or a threaded bolt extending therefrom are well-suited as ahard point for fixturing or hingeably attaching the finished vehiclecomponent to the vehicle as a whole.

While the inclusion of a strut 312 in a preform is illustrated in FIG.12 is formed with only a single sewing head, it is appreciated that astrut 312 is also readily employed with the multiple sewing headembodiment detailed with respect to FIG. 8.

FIG. 13A is a cross-section representation of the preform 310 with areinforcing strut 312 using a common naming convention relative to FIG.9. FIG. 13B is a cross-section representation of the preform 310 with atop placed reinforcing strut 312 and an inverted preform similar to thatshown in FIG. 10 and with partial layers 212′ that are complementarythereto. No stitches are shown for visual clarity.

FIGS. 14A-C are a series of schematics showing liquid composite molding(LCM) formation of a component 400. In FIG. 14A, fiber reinforcedpreform 110 or 210 or 310 or a combination thereof is brought intocontact with mold platen 410 and thermoset liquid resin 510 is poured onthe preform 110 or 210 or 310 or a combination thereof. In FIG. 14B, anopposing platen 412 is closed to define the volume V. With theapplication of heat, pressure, cure catalyst, or a combination thereof,the resin infiltrates the preform 110 or 210 or 310 or a combinationthereof and cures to form a matrix in a shape defining the component400. The volume V corresponding in shape to the vehicle component. In aspecific inventive embodiment, the preform is overlaid with at least onefabric sheet 414 that is permeated by the resin. Upon opening the volumeV, a completed component 400 is removed, as shown in FIG. 14C.

As shown in FIGS. 15A-C, in which like reference numerals have themeaning previously ascribed thereto a series of schematics illustrateRTM formation of a component 400′. In FIG. 15A, preform 110 or 210 or310 or a combination thereof is brought into contact with mold platen410 and opposing platen 412 is brought into contact to define the volumeV′. The volume V′ corresponding in shape to the desired component. Athermoset liquid resin 510 is injected through ports 418 into the volumeV′ to permeate the preform 110 or 210 or 310 or a combination thereof.In FIG. 15B, cure of the resin occurs with resort to the application ofheat, pressure, cure catalyst, or a combination thereof, the resininfiltrates the preform 110 or 210 or 310 or a combination thereof andcures to form a matrix in a shape defining the component 400′. In aspecific inventive embodiment, the preform is overlaid with at least onefabric sheet 414 that is permeated by the resin. Upon separating theplatens 410 and 412, a completed component 400′ is removed, as shown inFIG. 15C.

There are several types of RTM resin delivery systems available on thecommercial market that can be employed in the present invention. Thepump mechanism can be powered with one or a combination of pneumatic,hydraulic, or gear drive systems. Positive displacement pumping of theresin is well-suited for large complex components 400′ illustrativelyincluding vehicle applications and is characterized by constant pressureand continuous resin flow while also affording computer control of theinjection cycle.

It is appreciated that in some inventive embodiments one can maintain apredetermined hydrostatic resin pressure and adjust and display thetemperature for viscosity control as well as for resin flow rate andvolume control.

An exemplary RTM process according to the present invention includes,the (1) preform loading for structural applications at 10-65% by totalweight percent of the component; (2) applying vacuum to promote resinflow for complete wet out of the preform; (3) resin viscosity less than1000 cps allows lower injection pressure and faster injection, as doesmultiple port injection; (4) the mold platens are integrally heated toreduce cycle time and mold handling; (5) resin is previously degassed tominimize porosity and void content, unless a foaming agent is added; (6)hydrostatic pressure is held after resin injection to lower porositycontent; and, (7) injection pressure is less than 10 atmospheres toallow a slow-moving resin flow front and to limit resin containingfibers to become inhomogeneous as to density, orientation, or both.

FIGS. 16A-C are a series of schematics showing melt formation of avehicle component 400. In FIG. 16A, form 210 is intended to be broughtinto simultaneous contact with opposing mold platens 410 and 412 thatdefine a cavity volume, V. The volume V corresponding in shape to thedesired vehicle component. By selectively heating one or both of theplatens 410 or 412 to a temperature sufficient to melt the thermoplasticcontent of the form 210, but not the insulation surrounding anyelectrical wiring 121 included in the fiber bundle, a vehicle componentis formed upon cooling the mass compressed within the platens 410 and412 by temperature and pressure, as shown in FIG. 16B. In a specificinventive embodiment, a thermoplastic veil 414 is in contact one or bothplatens 410 and 412 to create a skin on the resulting vehicle component.Upon opening the volume V, a completed vehicle component 400 is removed,as shown in FIG. 16C.

According to embodiments, the inventive preform further includesadditional layers of material to form light-weight, high-strengthcomposite components, as shown in FIG. 17 that may be used as vehiclecomponents. According to embodiments, the fiber preform 10 of thecomposite material 39 is at least partially impregnated with a thermosetresin. According to various embodiments, the thermoset resin is appliedto the fiber preform 10 as a preformed sheet of thermoset resin 41, forexample a sheet molding compound (SMC). According to variousembodiments, the preformed sheet of thermoset resin contains a matrix ofpolyester material combined with reinforcing fibers. In variousembodiments, the sheet molding compound contains chopped fibers forreinforcement. For example, such chopped fibers illustratively includenatural, glass, aramid, carbon (high strength and high modulus) andceramic fibers.

The preformed sheet of thermoset resin may initially include a layer oftacky thermoset resin sandwiched between removable protective sheets.Upon removing either of the protective sheets, the tacky thermoset resinis exposed and free to adhere to another surface, for example a firstsurface 42 of the fiber preform 10, as shown in FIG. 18. The preformedsheet of thermoset resin is highly viscous when in sheet form, such thatit retains its shape and position between the protective sheets until itis heated. Once heated to a predesignated temperature, the thermosetresin becomes less viscous such that the resin flows more freely toimpregnate the fiber preform. According to some embodiments, thecomposite material 39 is formed by co-molding at least one sheet ofpreformed thermoset resin with the fiber preform. The co-molding mayinclude a heated compression mold. The heat of the co-molding processcauses the thermoset resin to become less viscous and to flow into thefiber bundle of the fiber preform. The composite material 39 may bemolded into vehicle components.

In some embodiments of the present disclosure, such as that shown inFIG. 19, a second sheet of preformed thermoset resin 41 is layered on asecond side 44 of the fiber preform 10. As described above, when heatedto the predetermined temperature, the thermoset resin becomes moreviscus and flows to impregnate the fiber preform 10. The amount of thefiber preform 10 that is impregnated with thermoset resin canaccordingly be tuned based on the number of sheets of preformedthermoset resin that are applied to the fiber preform. In someembodiments, the substrate 12 is removed from the fiber preform, priorto layering of the sheet or sheets of preformed thermoset resin to allowthe thermoset resin to more easily impregnate the fiber preform.

According to some forms, such as that shown in FIG. 20, the sheet orsheets of thermoset resin define a cutout 47 in the resin. The cutoutsmay be any suitable shape or orientation. The cutouts 47, provide areasfree of thermoset resin such that when the sheet of preformed thermosetresin is applied to the fiber preform 10 and the thermoset resin isheated and the resin impregnates the fiber preform, a portion of thefiber preform that is within the area of the cutout 47 remains free ofresin.

Referring again to FIG. 19, some forms of the inventive compositematerial include a protective layer 46 on an outside surface 48 of thesheet of preformed thermoset resin 41. This protective layer 46 may bethe protective layer initially provided with the sheet of preformedthermoset resin or the protective layer 46 may be added subsequently.When the protective layer 46 is co-molded with the fiber preform 10 andthermoset resin 41, the protective layer 46 provides a treatable surfacefinish for the composite material. The treatable surface may be a smoothsurface that is suitable for painting, i.e., a Class A automotivesurface.

The present disclosure further provides a method for making a componentformed of the composite material described above. As shown in FIGS.21A-21D, the method includes placing at least one sheet of preformedthermoset resin 41 into a mold 60. Placing the sheet of preformedthermoset resin 41 into the mold may include removing the initialprotective sheet from the thermoset resin to expose the tacky resin suchthat it may adhere to another surface. This may be done before or afterthe sheet of preformed thermoset resin in placed into the mold 60. Themethod continues by placing the fiber preform 10 onto the at least onesheet of preformed thermoset resin 41. It is envisioned that the sheetof preformed thermoset resin 41 and the fiber preform 10 can optionallybe layered together prior to being jointly placed into the mold.According to various embodiments, the method includes removing thesubstrate 12 from the fiber preform 10 so that the thermoset resin mayflow more easily into the fiber preform.

According to various embodiments and based on the design parameters ofthe final composite material 39 part, a second sheet of preformedthermoset resin 41 is applied to the fiber preform 10, as shown in FIG.21C. It is understood that any sheet of preformed thermoset resin 41that is used in the inventive process may include a protective sheet 46that may be co-molded with the thermoset resin 41 and the fiber preform10 to give the final composite material 39 a treatable surface finish,for example as shown on the second sheet of preformed thermoset resin 41shown in FIG. 21C.

The method continues by closing the mold 60 as shown in FIG. 21D.according to various embodiments, the mold 60 is a tape molding mold,accordingly eliminating the need to purchase separate overmoldingequipment to carry out the inventive process. The mold 60 applies heatand compression to the materials layered in the mold 60. When heat isapplied to the materials in the mold 60, the thermoset resin 41 becomesmore viscous and flows into the fiber preform to impregnate the fiberpreform with thermoset resin.

Often, it is desired that the composite materials formed using a fiberpreform of the present disclosure have a three-dimensional shape, forexample a curve, an angle, or some other non-planar configuration.Additionally, it is often desired to produce a composite part that has acorrugated core to increase strength of the composite part. Tomanufacture three-dimensional composite material parts, a fiber preformis placed in a mold having a three-dimensional shape corresponding tothe shape of the desired final composite material part. It has beenfound that typical fiber preforms formed using a selective comingledfiber bundle positioning process are difficult to place in suchthree-dimensional molds due in part to the floppy or limp nature of thetwo-dimensional fiber preform. Achieving a suitable fit between thegenerally two-dimensional fiber preform 10, as shown in FIG. 22, and athree-dimensional overmolding mold is difficult and often results inimproper fit in the mold, voids between the insert and the mold surfaceor wrinkles in the insert. Such voids, wrinkles, and other undesirablealignment issues lead to concentrations of resin, weak points, poorresin infiltration, and cracking in the final composite material parts.

Embodiments of the present invention provide a fiber preform capable ofbeing pre-shaped into a three-dimensional design before being placed inthe three-dimensional composite material mold. According to variousforms of the present invention, the fiber preform 10 may be placed on apre-shaping mold 70 such as those schematically shown in FIGS. 23 and24, however various other pre-shaping mold 70 shapes and configurationsare appreciated. Gravity may assist with seating the fiber preform 10 onthe pre-shaping mold 70. Providing a three-dimensional fiber preform 10such as those shown in FIGS. 25 and 26 is beneficial in that it helps toalleviate the above-identified problems. The non-planarthree-dimensional shape of the fiber preform 10 corresponds to the shapeof an overmolding, i.e. resin transfer molding (RTM), Liquid compositemolding (LCM), thermoplastic overmolding, or injection molding mold withwhich the fiber preform is to be used to form a composite part. As shownin FIGS. 25 and 26, the non-planar three-dimensional shape is a squarewave profile, which may be used as a corrugated core for a compositepart. Other suitable profile shapes are also contemplated includingthose shown in FIGS. 27A-F.

According to embodiments, heat may be applied to one or both sides ofthe fiber preform 10 by heat emanating from the pre-shaping mold 70 orfrom another source. According to some embodiments, in which athermoplastic thread is used to attached the fiber bundle to thesubstrate, when the fiber preform 10 is heated to the meltingtemperature, thermofusion of the thermoplastic thread of the pluralityof stitches takes place, and the thermoplastic thread melts and fuses toitself where the thread intersects itself, thereby forming tackingpoints throughout the fiber preform 10 such that the fiber preform 10conforms to and maintains a three-dimensional shape corresponding tothat of the pre-shaping mold 70.

According to various forms of the present invention, the fiber preform10 further includes a curable material applied to a portion of at leastone preform layer 11 to retain the fiber preform 10 in a non-planarthree-dimensional shape, as shown in FIGS. 25 and 26. According tovarious forms of the present invention, the curable material is a hightemperature epoxy, a high strength hair spray, an adhesive, a paint, orany combination thereof. Other curable materials capable to holding orretaining the fiber preform in a non-planar three-dimensional share arealso contemplated. Regarding additional suitable curable materialscontemplated by the present invention, “Preparing of Thermoset RubberyEpoxy Particles as Novel Toughening Modifiers for Glassy Epoxy Resis” byJansen et al., which is hereby incorporated by reference. The curablematerial may be applied as sparingly as needed such as in apredetermined pattern of dots and/or lines, or according to someembodiments, applied to an entire surface of the fiber preform.Alternatively, the fiber preform may be submerged in the curablematerial to coat all surfaces of the fiber preform. In some embodiments,the curable material is sprayed on by a machine or a human. In otherembodiments, the curable material is painted on by a machine or human.Combinations of spraying, painting, and submerging are also contemplatedherein.

According to some embodiments, pre-shaping the preform includes placingthe fiber preform 10 on a pre-shaping mold 70 such as that schematicallyshown in FIG. 23. Gravity may assist with seating the fiber preform 10on the pre-shaping mold 70. Upon heating the fiber preform 10 to amelting temperature at which point thermofusion of the thermoplasticthread of the plurality of stitches takes place, the thermoplasticthread melts and fuses to itself where the thread intersects itself,i.e. the tacking points throughout the fiber preform 10 such that thefiber preform 10 conforms to and maintains a three-dimensional shapecorresponding to that of the pre-shaping mold 70.

FIGS. 28A-28G show a method for forming a fiber preform 10 having athree-dimensional shape according to the present invention. As shown inFIG. 28A, the method includes providing a two-dimensional preformmaterial in a shaping mold 70. An isometric view of an exemplary shapingmold 70 can be seen in FIG. 24. Those having ordinary skill in the artwill appreciate that the shaping mold 70 can have alternate geometriesbased on the desired non-planar, three-dimensional shape of the fiberpreform. The exemplary shaping mold 70, shown in FIGS. 28A-28G includestwo square shaped channels extending through the shaping mold. Such ashaping mold is useful in producing a fiber preform having a square waveprofile that may be used as a corrugated core for an overmoldedcomposite material. As shown in FIG. 28B, simply draping the fiberpreform 10 on the shaping mold does not ensure a proper fit or alignmentwithin the shaping mold 70.

The method continues by urging the fiber preform 10 to conform to thethree-dimensional shape of the shaping mold 70. As shown in FIG. 28C,the urging step includes placing a shaping guide 74 on the fiber preform10 to press the fiber preform 10 into the three-dimensional shape of theshaping mold 70. In some embodiments of the present invention, theurging step includes applying a vacuum to the fiber preform 10 to drawthe fiber preform into conformity with the shaping mold 70. The vacuummay be located under the shaping mold and apply suction to the fiberpreform via holes in the base of the shaping mold. It is also envisionedthat shaping guides may be used in combination with a vacuum. As shownin FIGS. 29A-29F, various forms of shaping guides 74 are contemplatedincluding blocks, screens, horizontal plates, rods or bars, angledplates, and vertical plates respectively. The shaping guides 74generally have geometries corresponding to the voids in the shaping mold70. According to some embodiments, the shaping guides 74 may be placedon the fiber preform within the shaping mold 70 and clamped to theshaping mold 70. The shaping guides 74 may be formed of any suitablematerial capable of urging the fiber preform into the shaping mold.Various geometries of the shaping guides 74 may be used based on thedesign parameters of the fiber preform including the thickness of thefiber preform and whether it is desired to apply the curable material tomore or less of the fiber preform. For example, when using a shapingguide such as those shown in FIGS. 29A and 29C, the curable material maybe blocked from coating a portion of the fiber preform that is coveredby the shaping guide. When using shaping guides such as those shown inFIGS. 29B, 29D, 29E, and 29F, more of the surface of the fiber preformis exposed and therefore able to be coated with the curable material.

Once the fiber preform 10 has been urged into conformity with thethree-dimensional shape of the shaping mold 70, the method continues byapplying a curable material to the fiber preform. Applying the curablematerial to the fiber preform causes the fiber preform to retain thethree-dimensional shape of the shaping mold 70 when the curable materialcures. According to some embodiments, the substrate 12 of the fiberpreform is removed prior to applying the curable material. The curablematerial may be any of a high temperature epoxy, a high strengthhairspray, an adhesive, a paint, or a combination thereof. As shown inFIG. 28E, the curable material is sprayed on to the fiber preform 10 bya sprayer 76. The sprayer may be operated by a human or a machine. Inother embodiments, the curable material is painted on to the fiberpreform by a human or a machine. In some embodiments, the curablematerial is applied to at least one surface of the fiber preform.Alternatively, the fiber preform may be submerged in the curablematerial. It is envisioned that submerging the fiber preform in thecurable material may include submerging the shaping mold and shapingguides in the curable material as well. Those having ordinary skill inthe art will understand that the curable material may prevent resin toinfiltrate the fiber preform in an overmolding process, therefore it isdesirable in some embodiments to apply the curable material only on onesurface of the fiber preform, in only predesignated areas of the fiberpreform, or sparingly.

As shown in FIG. 28F, the method continues by removing the shapingguides 74 in instances when shaping guides were used. Finally, as shownin FIG. 28G, the fiber preform 10 is removed from the shaping mold 70once the curable material has cured. As shown in FIGS. 25 and 26, thefiber preform 10 retains the three-dimensional shape of the shapingguide 70. The three-dimensional fiber preform 10 may then be used in anovermolding process such as RTM or LCM to make a composite material.

According to embodiments of the present disclosure, an inventive fiberpreform 10, as described above, is used to reinforce stress prone areasof a composite vehicle component. Referring to FIG. 30, a compositematerial vehicle component 90 according the present invention is shownovermolded in a resin matrix. As best seen in FIG. 31, the vehiclecomponent 90 includes a core 91 and at least one reinforcing preform 10.Together, the core 91 and the reinforcing preform are overmolded in aresin matrix to form a complete composite material vehicle component.

Vehicle components according to the present disclosure illustrativelyinclude a vehicle hood, a vehicle trunk door, a vehicle door panel, avehicle bolster, vehicle post, a vehicle chassis, a pickup box, a cabload floor, a vehicle floor, a tailgate, a deck lid, a roof, a fender, awheel well, and body panels; heavy truck components that illustrativelyinclude the aforementioned and sleeping compartment sections, farmequipment components that illustratively include drive cab bodycomponents; motor home floors and wall panels; and marine products suchas decking, sound damping panels, and cockpit sections; and train carcomponents illustratively including seats, flooring, roof sections, andwalls.

According to embodiments of the present disclosure, the resin matrix isa curable thermoset resin. Thermoset resins operative hereinillustratively include vinyl esters, polyurethanes, epoxies, polyureas,benzoxazines, maleimides, cyanate esters, phenolics and polyimides. Eachalone, a combination thereof, or in the presence of a foaming agent. Theresin matrix may be used both neat and loaded with reinforcingparticulate and fiber fillers, or a combination thereof, depending ondesired characteristics of the final component.

As shown in FIG. 31, the core 91 has a geometry with a at least one edge92 a, 92 b, 92 c, 92 d. The geometry shown in the exemplary figures arefor illustration purposes only. One of ordinary skill in the art willreadily recognize that the core may be formed in any shape and have avariety of geometries, generally corresponding to a predesigned vehiclecomponent to be formed from the composite material and process describedherein. The edge of the core 91 may be an edge 92 a at narrowed sectionof the core 91 forming a flange, an edge 92 b of a corner or an openingto a corrugation 94, an edge 92 c surrounding or abutting a throughopening 95 in the core 91, a boundary edge 92 d of the core 91, or anyother area prone to stress concentration.

According to embodiments of the present disclosure, the core 91 isformed of a sheet molding compound. Sheet molding compound is a ready tomold material containing a matrix of polyester material combined withreinforcing fibers. In various embodiments, the sheet molding compoundcontains chopped fibers for reinforcement. For example, such choppedfibers illustratively include natural, glass, aramid, carbon (highstrength and high modulus) and ceramic fibers. Embodiments of thepresent disclosure include the core having a geometry or shape that hasa high aspect ratio, i.e. a ratio of width to height of an object, whichillustratively includes flanges, corners, protrusions, and corrugations.

Embodiments of the present disclosure provide that the geometry or shapeof the core 91 is formed by a compression molding process. CompressionMolding is a method of molding in which the molding material, forexample sheet molding compound, is generally preheated and placed in anopen, heated mold cavity. The mold is closed with a top force or plugmember, pressure is applied to force the molding material into contactwith all mold areas, while heat and pressure are maintained until themolding material has cured. Compression molding is a high-volume,high-pressure method suitable for molding complex, high-strength, large,intricate parts.

As shown in FIG. 31, at least one insert reinforcing preform 10 of thevehicle component 90 is positioned along at least one of the edges 92a-92 d of the core 91 to strengthen and reinforce the edge or edges 92a-92 d. One having ordinary skill in the art will readily understandthat, based on desired performance characteristics and designspecifications, a vehicle component according to the present disclosuremay have anywhere from a single edge to all of the edges of the corereinforced with an insert reinforcing preform 10.

According to embodiments of the present disclosure, an insertreinforcing preform 10 is formed of a fiber bundle 14 of reinforcingfibers and or matrix fibers arranged in a shape corresponding to theedge 92 a-92 d which the insert reinforcing preform 10 is to reinforce.For example, if an insert reinforcing preform 10 is to reinforce alinear edge such as at a flange edge 92 a, an edge 92 b of an opening toa corrugation, or a boundary edge 92 d of the core 91, the insertreinforcing preform 10 is formed of a fiber bundle 14 arranged in agenerally linear shape to correspond to the linear edge 92 a, 92 b, 92d. It is also contemplated that when the edge to be reinforced has anon-linear shape, such as the edge 92 c of a through opening 95 or othernon-linear shapes, the insert reinforcing preform 10 is formed of afiber bundle 14 arranged in a corresponding generally non-linear shape.

As described above, embodiments of the present disclosure provide thatthe fiber bundle 14 is made of reinforcing fibers, such as those made of100% carbon, 100% glass, or 100% aramid fibers, or a combinationthereof. According to some embodiments, the fiber bundle 14 includesmatrix fibers in addition to the reinforcing fibers. The matrix fibersbeing of a thermofusible nature may be formed from a thermoplasticmaterial such as, for example, polypropylenes, polyamides, polyesters,polyether ether ketones, polybenzobisoxazoles, polyphenylene sulfide;block copolymers containing at least of one of the aforementionedconstituting at least 40 percent by weight of the copolymer; and blendsthereof. The thermoplastic fibers are appreciated to be recycled,virgin, or a blend thereof. The thermofusible thermoplastic matrixfibers have a first melting temperature at which point the solidthermoplastic material melts to a liquid state. The reinforcing fibersmay also be of a material that is thermofusible provided theirthermofusion occurs at a temperature which is higher than the firstmelting temperature of the matrix fibers so that, when both fibers areused to create a composite, at the first melting temperature at whichthermofusibility of the matrix fibers occurs, the state of thereinforcing fibers is unaffected.

As shown in FIG. 32, embodiments in which the fiber bundle 14 isattached to a substrate 12, the substrate acts as a foundation or baseupon which a fiber bundle 14 is applied. The substrate 12 may be atear-off fabric or paper or other suitable material. According to someembodiments, the fiber bundle 14 is applied and attached to thesubstrate 12 by a plurality of stitches 18 of a thread, which accordingto some embodiments is a thermoplastic thread, such as nylon. Theplurality of stitches 18 are shown in various zig-zag stitcharrangements. For example, the stitches may be closely spaced stitchesor spaced apart by a greater linear distance. The stitches may becontinuously connected along the fiber bundle 14, or the stitches may bediscrete and separate single stitches or separate groups of stitches.The plurality of stitches of thread may also attach the fiber bundle toitself. According to some embodiments, the substrate 12 may be removedcompletely from the fiber bundle 14 or can be partially removed or cutaway prior to placement of the insert reinforcing preform 10 on the core91. Alternatively, the insert reinforcing preform 10 may be formedwithout a substrate. In such embodiments, the fiber bundle 14 isattached to itself by a plurality of stitches of a thread, by anadhesive, or by a mechanical fastener. In some embodiments, the insertreinforcing preform 10 is formed directly on the core 91 by arrangingthe fiber bundle 14 on the core 91. The fiber bundle 14 is arrangedalong an edge 92 a-92 d of the core 91 and attached to the core 91 by aplurality of stitches or thread, by an adhesive, or by at least onemechanical fastener. For example, the adhesive may be hot glue,superglue, a double-sided tape, or a spray adhesive. Examples ofmechanical fasteners include staples, binder clips, clips, brads, bobbypins, pins, needles, and paper clips.

For embodiments in which the insert reinforcing preform 10 is formedseparately from the core 91, i.e. not formed directly on the core 91,the insert reinforcing preform 10, whether with a substrate or not, ispositioned relative to the core 11 prior to being overmolded. Eachinsert reinforcing preform 10 is positioned along the edge 92 a-92 d itis designed to reinforce. According to some embodiments, each insertreinforcing preform 16 is attached to the core 91 by an adhesive, atleast one mechanical fastener, or a combination thereof. For example,the adhesive may be hot glue, superglue, a double-sided tape, or a sprayadhesive. Examples of mechanical fasteners include staples, binderclips, clips, brads, bobby pins, pins, needles, and paper clips. Themechanical fasteners listed may be formed of, for example, a metalmaterial to provide further reinforcement of the edge or a plasticmaterial. In some embodiments, the plastic material forming themechanical fastener is a thermofusible thermoplastic that become lessviscous when heated, for example during overmolding, to further attachor fuse the insert reinforcing preform 16 to the core 11 and strengthenthe associated edge 92 a-92 d.

As shown in FIG. 33, in some embodiments, the insert reinforcing preform10 includes a plurality of extensions that extend away from the fiberbundle 14 of the insert reinforcing preform. The extensions 93 areattached to the insert reinforcing preform 10 at the first end of eachextension 93. The extensions 93 may be attached to the insertreinforcing preform 10 by stitches of a thread, by an adhesive, or bymechanical fasteners. According to some embodiments, the extensions 93are dangling portions of the fiber bundle 14 or dangling fibers of thefiber bundle, for example reinforcing fibers or thermofusible fibers ofthe fiber bundle 14. The extensions 93 may be formed while the insertreinforcing preform is formed, for example by creating loose loops ofthe fiber bundle 14 as the fiber bundle is arranged, for example on asubstrate or on the core 91. The extensions 93 may also be formed bypulling fibers loose from the fiber bundle before, during, or after, thefiber bundle 14 is arranged to form the insert reinforcing preform 10.The extensions 93 may also be formed by attaching them to the fiberbundle 14 after the insert reinforcing preform is formed.

The extensions 93 provide further attachment between the insertreinforcing preform 10 and the core 91 and strengthen the associatededge 92 a-92 d. The extensions 93 extend from the insert reinforcingpreform onto various sections of the core 91. Depending on the positionof the insert reinforcing preform from which the extensions extend, theextensions 93 may extend into corrugations 94 in the core 91, along thecore 91 radiating away from through openings 95 or other edge features92 a-92 d. When the vehicle component 90 is overmolded in the resinmatrix, the extensions 93 provide more interaction points between theinsert reinforcing preform 10 and the core 91. In cases where theextensions 93 include reinforcing fibers, such as those in the fiberbundle 14, the extensions 93 provide increased reinforcement of thevehicle component 90. In cases where the extensions 93 includethermofusible fibers, such as those that may be used in the fiberbundler 14, the extensions 93 provide further points of fusion betweenthe insert reinforcing preform 10 and the core 91.

The present disclosure further provides a method of making the vehiclecomponent described above. In addition to the forming methods describedabove, the method includes providing the core 91 having the at least oneedge 92 a-92 d, positioning at least one insert reinforcing preform 10along at least one edge 92 a-92 d of the core 91; and overmolding thecore 91 and the insert reinforcing preform 10 in a resin matrix.

The method may first include giving the core 91 its predesigned shape orgeometry, which according to some embodiments includes compressionmolding a sheet molding compound. According to some embodiments,providing the core includes positioning the core in an overmolding mold.According to embodiments of the present disclosure, the insertreinforcing preform 10 is positioned on the core 91 after the core 91 ispositioned in the overmolding mold. Alternatively, the core 91 andinsert reinforcing preform 10 may be positioned relative to one anotherprior to being placed in a mold.

In some embodiments, the method further includes forming an insertreinforcing preform 10. As described above, an insert reinforcingpreform is formed by arranging a fiber bundle 14 in a shapecorresponding to the edge 92 a-92 d that the preform is to reinforce.The fiber bundle may be arranged separately from the core 91 or directlyupon the core 91. The fiber bundle may be arranged on a substrate 12.Once arranged on the substrate 12 or the core 91, the fiber bundle 14 isattached to itself, the substrate, the core, or a combination thereof.According to some embodiments, the method includes removing thesubstrate entirely or partially by, for example tearing or cutting atleast a portion of the substrate from the insert reinforcing preform,for example along the dotted line shown in FIG. 32.

In further embodiments, the method includes forming extensions thatextend from the insert reinforcing preform 10. The extensions 93 may beformed while the insert reinforcing preform is formed, for example bycreating loose loops of the fiber bundle 14 as the fiber bundle isarranged, for example on a substrate or on the core 91. The extensions93 may also be formed by pulling fibers loose from the fiber bundlebefore, during, or after, the fiber bundle 14 is arranged to form theinsert reinforcing preform 10. The extensions 93 may also be formed byattaching them to the fiber bundle 14 after the insert reinforcingpreform is formed.

According to embodiments, positioning the insert reinforcing preform 10on the core 91 includes attaching the insert reinforcing preform 10 toan edge 92 a-92 d using an adhesive, stitches of a thread, or at leastone mechanical fastener. In cases where the insert reinforcing preform10 includes extensions 93, positioning the insert reinforcing preform 10on the core 91 includes ensuring that the extensions 93 extend from theinsert reinforcing preform either into corrugations 94 of the core 91 oralong the core 91.

The foregoing description is illustrative of particular embodiments ofthe invention, but is not meant to be a limitation upon the practicethereof. The following claims, including all equivalents thereof, areintended to define the scope of the invention.

1. A fiber preform for use in a molding process, the fiber preformcomprising: a substrate; a fiber bundle comprising one or more types ofreinforcing fibers; a thread; and wherein the fiber bundle is arrangedon the substrate and attached to the substrate by a plurality ofstitches of the thread to form a first preform layer having a principalorientation.
 2. The fiber preform of claim 1 wherein the one or moretypes of reinforcing fibers comprise carbon fiber, glass fiber, andaramid fiber.
 3. The fiber preform of claim 1 wherein the fiber bundlefurther comprises matrix fibers of thermoplastic material.
 4. The fiberpreform of claim 1 wherein the fiber bundle includes a subset of yarnfibers, a subset of roving fibers, or a combination thereof.
 5. Thefiber preform of claim 1 wherein the fiber preform is formed of a singlecontinuous fiber bundle.
 6. The fiber preform of claim 1 wherein thefiber preform is formed of at least two separate fiber bundles.
 7. Thefiber preform of claim 1 wherein the fiber preform is tunable based oncontrolling parameters of the fiber bundle, the thread, the plurality ofstitches, or a combination thereof.
 8. The fiber preform of claim 1further comprising a plurality of subsequent preform layers formed ofthe fiber bundle and successively stacked from the first preform layer,each subsequent preform layer arranged on a preceding preform layer andattached to the preceding preform layer by additional stitches of thethread.
 9. The fiber preform of claim 8 wherein an orientation of eachsubsequent preform layer is offset from that of the preceding preformlayer by an angular displacement relative to the principal orientationof the first layer.
 10. The fiber preform of claim 1 wherein the threadis a non-melting fiber of polyaramid, carbon, glass, or a combinationthereof or is a thermoplastic thread.
 11. The fiber preform of claim 1further comprising secondary tack points throughout the fiber bundle toattach the fiber bundle to itself.
 12. The fiber preform of claim 1wherein the thermoplastic thread is melted to retain the fiber preformin a non-planar three-dimensional shape.
 13. The fiber preform of claim1 wherein the fiber preform is impregnated with a thermoset resin toform a vehicle component.
 14. The fiber preform of claim 1 furthercomprising at least one of insulated electrical wiring and a printedcircuit board stitched into the fiber preform.
 15. A composite materialcomprising: the fiber preform of claim 1; at least one sheet ofpreformed thermoset resin layered on a first side of the fiber preform;wherein the sheet of preformed thermoset resin becomes less viscus whenheated such that the thermoset resin impregnates at least a portion ofthe fiber preform.
 16. The composite material of claim 15 wherein thefiber bundle comprises carbon fibers, glass fibers, aramid fibers, or acombination thereof.
 17. The composite material of claim 15 wherein thefiber bundle further comprises thermoplastic fibers.
 18. The compositematerial of claim 15 wherein the fiber preform includes electricalwiring stitched thereto.
 19. The composite material of claim 15 whereinthe at least one sheet of preformed thermoset resin is a sheet moldingcompound.
 20. The composite material of claim 15 wherein the at leastone sheet of preformed thermoset resin includes a protective layer on anoutside surface of the sheet of preformed thermoset resin that whenco-molded with the fiber preform and thermoset resin provides atreatable surface finish for the composite material.